CEO SUMMARY: Proponents of digital pathology systems and whole slide imaging achieved a milestone on April 12 when the FDA cleared the Philips digital pathology system for sale in the United States. Now pathologists can use the system to perform primary diagnoses and get paid for those professional services. It is expected that this regulatory clearance will encourage more pathology group practices to consider acquiring their own digital pathology systems.

DIGITAL PATHOLOGY AND WHOLE SLIDE IMAGING just cleared one of its toughest regulatory hurdles in the United States. On April 12, the Food and Drug Administration cleared the Philips IntelliSite Pathology Solution (PIPS) for sale in the United States.

In announcing its decision, the FDA said that the Philips product is a “whole slide imaging (WSI) system that allows for review and interpretation of digital surgical pathology slides prepared from biopsied tissue. This is the first time the FDA has permitted the marketing of a WSI system for these purposes.”

Alberto Gutierrez, PhD, Director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health, said, “The system enables pathologists to read tissue slides digitally in order to make diagnoses, rather than looking directly at a tissue sample mounted on a glass slide under a conventional light microscope.”

The FDA’s decision is significant because it gives Philips the first digital pathology system cleared for use in the primary diagnosis of tissue specimens, a significant milestone for digital pathology technology in the United States.

Two things can be expected to happen in response to the FDA’s action. First, other manufacturers of digital pathology systems will file applications for market clearance and use the application Philips submitted as a guide. Within a year or two, other digital pathology systems will likely gain FDA clearance.

Second, it is widely believed that pathology groups and pathology lab companies have held off buying digital pathology systems until federal regulators cleared the technology for use in the primary diagnosis of biopsied tissue and resection cases. Now that Philips has won such clearance, there is likely to be a surge in demand for these systems.

This FDA clearance comes almost 20 years after the first telepathology and digital pathology systems entered the market. Most of those systems were used for research and internal purposes, such as teaching, tumor boards, and consults.

For Philips, this regulatory decision comes after seven years of development work and market engagement. “This FDA decision has been a long time coming and it feels good to make a difference in the industry by making the promise of digital technology applicable to what pathologists do every day,” stated Russ Granzow, General Manager of Philips Digital Pathology Solutions. “The Philips IntelliSite Pathology Solution (PIPS) was demonstrated for the first time at USCAP 2010 and Philips signed the first contract for the system in 2011. That is well before it was possible for pathologists to get paid for using the system for primary diagnosis.”

A Complicated Question

While recognizing the importance of the FDA’s decision, Granzow was not ready to say that pathologists will do away with microscopes any time soon. “Will digital pathology systems replace the microscope?” he asked. “The transition towards a full digital workflow is a significant effort for the lab. The fact that the FDA approved the use of digital pathology for primary diagnosis is certainly an important milestone.

“The FDA’s decision truly is a watershed moment for pathologists who now have the power to do primary diagnosis with any histology tissue type and any stain using digital pathology equipment,” he noted. “Bringing digitization to the industry means we can leverage all the benefits that result when images are digitized. This includes enhanced logistics, and easier collaboration, as well as the future use of artificial intelligence and all the other digital tools and data to help pathologists be more effective in this new complex world of healthcare.”

Faster Diagnoses

The FDA recognized these benefits as well. “Because the system digitizes slides that would otherwise be stored in physical files, it also provides a streamlined slide storage and retrieval system that may ultimately help make critical health information available to pathologists, other health care professionals, and patients faster,” Gutierrez said in the FDA announcement.

The use of digital imaging will require labs to make significant and costly changes in workflow. “Some labs are very keen to make those changes because they believe that digital pathology systems mean they can improve quality and ultimately outcomes—we believe,” Granzow said. “Those workflow changes will take time and money, which means some labs will adopt whole slide imaging right away and others will not.

“But regardless of how fast pathologists adopt digital workflow systems, the FDA approval is truly a watershed moment for all pathology groups,” he added. “One reason this is true is because pathologists now have an easier path to realize a return on investment from their use of a digital pathology system.

“This is the important point about the FDA’s decision: It means that pathologists can charge and get reimbursed for the professional component of doing a standard diagnosis for H&Es, IHCs, and special stains,” emphasized Granzow. “The reimbursement codes already exist.

“ROI was beginning to become attractive just from the workflow improvements that pathologists would get and that was without being able to charge for and get paid for primary diagnosis,” he said.

“Now, with FDA clearance of our digital pathology system, it is possible for pathologists to get both workflow improvements and the big benefit of getting paid for using imaging for primary diagnosis. Those two factors will cause more pathologists to consider adopting digital pathology.

“Payment is important, of course, but don’t overlook the fact that workflow is also a significant factor in any pathologist’s decision to adopt an imaging system,” Granzow added. “Our solution has always been focused on very efficient clinical workflow. You load the system, close the door, and there is no other human interaction after that. Slides are scanned and go to your image management system. It is designed for hands-off, very high throughput clinical workflow. That’s what pathologists are looking for today.”

Philips would not say how many pathology groups have installed the PIPS system in the United States. Granzow said, “It’s in the hundreds of users and is significant,” adding that the PIPS system is used by major academic medical centers, comprehensive cancer centers, and reference laboratories.

WHEN IT ANNOUNCED THE CLEARANCE FOR MARKET of the Philips IntelliSite Pathology Solution (PIPS) for whole slide imaging (WSI), the FDA said the system can scan and digitize conventional surgical pathology glass slides prepared from biopsied tissue at resolutions equivalent to 400 times magnification. Pathologists then can view the digitized images for interpretation.

The FDA based its approval of the PIPS for primary diagnosis on a clinical study of approximately 2,000 surgical pathology cases using tissue from multiple anatomic sites. “Results of the study found that clinical interpretations (diagnoses) made based on the PIPS images were comparable to those made using glass slides,” the FDA said.

Philips sponsored the study at the Cleveland Clinic, the University of Virginia, Advanced Pathology Associates in Rockville, Md., and Miraca Life Science in Irving, Texas.

The fact that the researchers concluded that clinical interpretations of digital images were comparable to those that a pathologist would make while viewing glass slides is the significant factor in the decision. To the researchers, the term “comparable to” meant pathologists could make interpretations that were “not inferior to” those made using glass slides.

When the researchers described the study in a poster presented at USCAP 2017, they said, “Before substituting the time-honored, familiar, and versatile microscope with digital microscopy, several valid concerns need to be addressed. The most critical issue is whether pathologic diagnoses rendered using WSI are comparable to (i.e. non-inferior to) pathologic diagnoses made with optical microscopy.”

While several smaller and single-site studies were done previously, the research Philips sponsored was more robust. “This large, multi-center, non-inferiority study compares microscopy to WSI reads of 2,000 surgical pathology cases from 20 different organ systems (54 subtypes) with 16 reading pathologists from four institutions,” the study by Feldman, Rubin, et. al, showed.

In their conclusions, the researchers wrote, “Manual digital is non-inferior to manual optical for primary diagnosis for surgical pathology. Manual digital is non-inferior to manual optical across a wide range of organ systems and pathologists.”